A. Field of the Invention
The invention relates to tools associated with engine repair, specifically to tools associated with installation of valve keepers.
B. Related Art
The springs on the intake and exhaust valves of conventional internal combustion engines act against spring washers which are detachably locked to the stems of the valves by means of split, conical valve keepers which interfit the spring washers and engage at least one circumferential groove in the stem of the valve to retain the spring washer in place against the expansive pressure of the spring. In certain types of engines the valve stems and the stem surrounding springs are positioned in indentations or sockets in the block or cylinder head of the engine so that it may be difficult to reach the stems and springs and properly position the retainers in operating position when installing the valve assemblies in the engine.
When installing the keepers, it is necessary to hold the valve in place, to compress the spring, and to simultaneously place two small keepers in the proper position against the valve stem. This task is difficult under the best of circumstances, but it is even more difficult when there is more than one circumferential groove in the valve stem. In such a case, the keepers must be held out some distance from the stem while the keeper is pushed down until each groove engages the correct corresponding ridge on each keeper.
A particular problem is encountered using existing tools to try to place valve keepers with multiple circumferential grooves. When existing tools are used, the keepers slide downward onto the stem, and the first circumferential groove encounters the first ridge on the keeper, and prevents it from continuing downwardly so that the proper groove can contact the proper ridge. Mechanics have dealt with this difficulty by resorting to crude makeshift solutions. For example, a mechanic may stick each half of the keeper to a regular screwdriver using grease, then carefully try to ease both halves down into the proper position where each groove is set to encounter the proper ridge before contacting the keepers with the stem. These makeshift solutions to the problem have been difficult and time-consuming resulting in frustration for the mechanic and additional costs for the person whose engine is being repaired.
An additional problem with prior tools for installation of valve keepers is that many were designed to operate with a specific size of valve keeper. There was no way to accommodate a variety of sizes of keepers. Thus, a variety of tool sizes had to be kept on hand, and the proper one had to be selected for the particular size/type of keeper being installed. See, for example, U.S. Pat. No. 3,316,623 to Clark showing a tool that would only accommodate a narrow range of keepers as well as a narrow range of valve stem sizes.
There was thus a need for a valve keeper installation tool that could accommodate a range of valve stem sizes and, at the same time, be used with a range of valve keeper sizes.